Method of producing a veneered element and such a veneered element

ABSTRACT

A method of producing a veneered element, the method including providing a substrate, applying a sub-layer on a surface of the substrate, applying a veneer layer on the sub-layer, and applying pressure to the veneer layer and/or the substrate, such that at least a portion of the sub-layer permeates through the veneer layer. Also, such a veneered element.

TECHNICAL FIELD

The disclosure relates to a method of producing a veneered element andsuch a veneered element.

TECHNICAL BACKGROUND

Floor coverings having a wooden surface may be of several differenttypes. Solid wood flooring is formed of a solid piece of wood in form ofa plank. Engineered wood flooring is formed of a surface layer of woodglued to a core. The core may be a lamella core or a wood-based panelsuch as plywood, MDF or HDF. The wooden surface layer may as an examplehave a thickness of 2-10 mm.

A wooden floor covering may also be formed by gluing a wood veneer to acore, for example, a wood-based panel such as particleboard, MDF or HDF.Wood veneer is a thin wood layer, for example having a thickness of0.2-1 mm. A flooring with a separate surface layer glued to a core offor example HDF or plywood is more moisture stable than solid woodfloorings.

Compared to solid wood and engineered wood floorings, wood veneerfloorings can be produced to a lower cost since only a thin wood layeris used. However, a wood veneer layer cannot be sanded as a solid woodor engineered wood flooring can be.

As an alternative to wood floorings, laminate floorings are alsoavailable. Direct pressed laminated flooring usually comprises a core ofa 6-12 mm fibre board, a 0.2 mm thick upper decorative surface layer oflaminate and a 0.1-0.2 mm thick lower balancing layer of laminate,plastic, paper or like material.

A laminate surface conventionally comprise two paper sheets, a 0.1 mmthick printed decorative paper and a transparent 0.05-0.1 mm thickoverlay intended to protect the decorative paper from abrasion. Thetransparent overlay, which is made of α-cellulose fibres, comprisessmall hard and transparent aluminium oxide particles, which gives thesurface layer a high wear resistance.

The printed decorative paper and the overlay are impregnated withmelamine resin and laminated to a wood fibre based core under heat andpressure. The two papers have prior to pressing a total thickness ofabout 0.3 mm and they are after pressing compressed to about 0.2 mm.

A wood veneer may have a lower impact resistance than laminate flooringsand the production cost is high, compared to laminate floorings, whenhigh quality veneers are to be used.

Recently new “paper free” floor types have been developed with solidsurfaces comprising a substantially homogenous powder mix of fibres,binders and wear resistant particles referred to as WFF (Wood FibreFloor). The mix is applied on a wood-based panel such as MDF or HDF, andsubsequently applying heat and pressure to the mix to form a surfacelayer on the panel. Such a flooring and process are described in WO2009/065769.

WO 2009/065769 also discloses a thin surface layer such as wood veneerlayer, which is applied on a sub-layer comprising, for example, cork orwood fibres mixed with a binder. The sub-layer is applied on wood fibrebased core.

U.S. Pat. No. 2,831,794 discloses a process for manufacturing veneerpanels. A green veneer is applied on a mat of resin coated coreparticles of ligno-cellulose fibrous particles. Adhesive is applied onthe veneer to bond the veneer to the fibrous core, and to form a densesurface zone in the fibrous core. The material of the core serves tofill knot holes or open flaws in the veneer. When heat and pressure isapplied, the result is the formation of a panel, with the surface layerof the particles filling whatever flaws or holes would otherwise thepresent in the veneer.

U.S. Pat. No. 2,419,614 discloses a coated wood product wherein aplywood is coated by a covering or overlay material consisting ofmixtures of sawdust and synthetic resin. The veneer layer is coated bythe covering or overlay material such that the veneer is no longervisible. The covering forms the uppermost layer of the product.

In the above description, the different types of product have beendescribed with reference to floorings. However, the same material andproblems applies for other types of building panels such as wall panels,ceiling panels, and for furniture components.

SUMMARY

It is an object of at least embodiments of the present invention toprovide an improvement over the above described techniques and knownart.

A further object of at least embodiments of the present invention is toimprove properties of a veneer surface.

A further object of at least embodiments of the present invention is toimprove the wear resistance of a veneer surface.

A further object of at least embodiments of the present invention is toreduce the cost for producing surface with an attractive design.

A further object of at least embodiments of the present invention is touse veneers of low quality and/or thin thickness.

A further object of at least embodiments of the present invention is toprovide a wood veneer surface having the look of a solid wood surface.

A further object of at least embodiments of the present invention is toprovide a veneer surface having an attractive design.

A further object of at least embodiments of the present invention is tocontrol the design of a veneer surface.

A further object of at least embodiments of the present invention is toimprove water resistance of a veneer surface.

At least some of these and other objects and advantages that will beapparent from the description have been achieved by a method ofproducing a veneered element, comprising

-   -   providing a substrate,    -   applying a sub-layer on a first surface of the substrate,    -   applying a veneer layer on the sub-layer, and    -   applying pressure to the veneer layer and/or the substrate, such        that at least a portion of the sub-layer permeates through the        veneer layer.

Said at least a portion of the sub-layer may permeate at least partlythrough the veneer layer, or may permeate completely through the veneerlayer.

Preferably, the method may further comprise applying a protective layercomprising a thermoplastic material on the veneer layer. The protectivelayer may be applied on the veneer layer prior or after the step ofapplying pressure to the veneer layer and/or the substrate. If theprotective layer is applied on the veneer layer prior to applyingpressure, pressure is applied to the veneer layer via the protectivelayer. In one embodiment, the protective layer is applied on the veneerlayer after the step of pressing, and is attached to the veneer layer inan additional step, for example, by pressing.

An advantage of at least certain embodiments is that the protectivelayer comprising the thermoplastic material protects the veneer layer.By arranging a protective layer comprising thermoplastic material on theveneer layer, a substrate having a veneer surface layer being waterproofmay be obtained. The protective layer contributes with water resistantproperties to the veneer layer, such that a waterproof surface layer isobtained, wherein the decorative properties of the substrate are formedby the veneer layer.

Furthermore, the gloss level of the protective layer may be determinedby the press plate or press belt when pressing the protective layer tothe veneer layer.

The protective layer is preferably transparent, or at leastsubstantially transparent.

The method may further comprise applying the protective layer to atleast a portion of an edge surface of the substrate, for example, abevel formed along an edge of the substrate. Thereby, also an edgeportion of the substrate is protected by the protective layer such thatthe water resistance of the veneered element is further improved.

The thermoplastic material may comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The protective layer maycomprise more than one thermoplastic material.

The protective layer may comprise one or more layers, wherein the layermay comprise different thermoplastic materials, or thermoplasticmaterial of the same type.

The protective layer may be at least one thermoplastic foil.

The protective layer may further comprise wear resistant particles. Thewear resistant particles may be applied between a first and a secondlayer of the protective layer. Alternatively, the wear resistantparticles may be applied on the veneer layer prior to applying theprotective layer. At least some of the wear resistant particles willprotrude from upper portions of the protective layer, or be arranged inthe upper portions of the protective layer, after pressing. Thereby, thewear resistant particles provide wear resistance to the protectivelayer.

The step of applying the protective layer may comprise applying thethermoplastic material in powder form on the veneer layer. Thethermoplastic material in powder form may be mixed with wear resistantparticles.

The step of applying the protective layer may comprise applying a firstfoil comprising a first thermoplastic material, on the veneer layer, andapplying a second foil comprising a second thermoplastic material on thefirst foil, wherein the first thermoplastic material is different fromthe second thermoplastic material.

The first and second thermoplastic material may be any of polyvinylchloride (PVC), polyester, polypropylene (PP), polyethylene (PE),polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET),polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

In one embodiment, the first thermoplastic material is polyvinylchloride (PVC). The second thermoplastic material may be polyurethane(PU). Compared to a conventional protective layer substantiallyconsisting of polyvinyl chloride, a protective layer comprising an upperportion of polyurethane obtains improved chemical resistance. Its scuffresistance and micro scratch resistance are also improved. An upperlayer of polyurethane also provides improved resistance against blackheel mark.

The method may further comprise controlling a design of the veneer layerby controlling permeation of the sub-layer through the veneer layer.Preferably, controlling a design of the veneer layer is performed bydetermining a level of permeation of the sub-layer through the veneerlayer. Determining a level of permeation may involve selecting oradjusting the permeation. This may involve selecting or adjusting afluid pressure of the sub-layer when applying pressure.

By controlling is meant determining, selecting and/or adjusting.

By determining is, for example, meant determining by visual impressionof the design of the veneer layer.

Preferably, at least a portion of the sub-layer is visible at thesurface of the veneer layer facing away from the substrate.

The substrate is preferably a pre-fabricated substrate. Preferably, thesubstrate is manufactured in a preceding manufacturing process.

An advantage of at least certain embodiments is that the surface designof the veneered element may be changed or altered by a portion of thesub-layer permeating through the veneer. By applying pressure to theveneer layer and/or the substrate, a part of the sub-layer flows throughpores, or cracks or holes, of the veneer such that a part of thesub-layer becomes visible at the surface of the veneer facing away fromthe substrate. Thereby, the design of the veneer is changed, especiallyif the sub-layer comprises pigments. A new design can be created, orfeatures of the veneer such as cracks and knots can be intensified bythe sub-layer being visible at the surface of the veneer.

The veneer layer forms the visible surface of the veneered element. Thedesign of the veneer layer, permeated by at a least a portion of thesub-layer, forms the design of the veneered element.

The veneer layer may also be reinforced by being arranged on thesub-layer. Further, the veneer layer may obtain improved wear resistantproperties by being at least partly impregnated by the sub-layer. Thesub-layer arranged under the veneer layer may also improve impactresistance properties of the veneer. The sub-layer may comprise a binderor lacquer giving the veneer improved wear resistant properties. Thesub-layer may also comprise wear resistant particles.

Since the sub-layer also flows into the substrate during pressing, thesub-layer provides improved impact, surface soundness, adhesivecapacity, reduced swelling, etc.

A further advantage of at least certain embodiments is that waterresistance of the veneer layer is improved. During pressing, the veneerlayer is compressed. Furthermore, during pressing, the binder flows intopores into the veneer and if a thermosetting binder is used, cures andthe veneer layer is at least partially locked in this compressed statedue to the cured binder holding the veneer layer in this position.Thereby, pores of the veneer layer are at least partially filled withthe binder such that water resistance of the veneered element isimproved.

Furthermore, an advantage of at least certain embodiments is that thesub-layer may fill any cracks, holes, or knots of the veneer layer.Thereby, there is no need, or at least a reduced need, to putty cracks,holes or knots of the veneer layer. Thereby, a costly operation oftenmade by hand is eliminated or at least reduced by arranging the veneerlayer on a sub-layer when pressing the veneer to the substrate.

By arranging the veneer on the sub-layer, and by at least a part of thesub-layer flowing through the veneer such that cracks, cavities or knotsare filled by the sub-layer, a thinner veneer may be used, or a veneerof lower quality may be used, for example, containing moreirregularities and defects.

Furthermore, by including pigments in the sub-layer, the veneer may becoloured. A glazing effect, a lazuring effect and/or staining effect maybe obtained.

By including additives to the sub-layer, the properties of the veneerlayer may be changed. For example, sound-absorbing fillers, such as corkparticles, may be added to the sub-layer to improve the sound absorbingproperties of the veneered element. Anti-static agents may be added tothe sub-layer. Additives improving the heat transfer of the veneeredelement may also be added.

In an embodiment wherein the substrate is a core, the core and theveneered element being bonded to the core form a building panel or afurniture component. The building panel may be a floor panel, a ceilingpanel, a wall panel, a door panel, a worktop, skirting boards,mouldings, edging profiles, etc.

In an embodiment, the veneered element is formed as a separate element,which later may be adhered to a component. The substrate may be acarrier for the veneer layer and the sub-layer, or may be a temporarycarrier from which the veneer layer and the sub-layer later are removed.

The method may further comprise controlling permeation of the sub-layerthrough the veneer layer. By controlling is meant, here and in thefollowing, determining, selecting and/or adjusting. Thereby, the designand appearance of the surface may be varied and controlled by varyingand controlling fluid pressure, binder concentration, type of binder,filler concentration, veneer properties, etc. By controlling theseparameters, the amount of the sub-layer which permeates the veneer layercan be controlled, and thereby the design of the veneer layer can bechanged in a controlled manner.

The method may further comprise processing the veneer layer by abrasivemachining prior to applying pressure to the veneer layer and/or thesubstrate. The method may further comprise brushing the veneer layerprior to applying pressure to the veneer layer and/or the substrate. Byabrasive machining the veneer layer, material from the veneer layer ismechanically removed.

In one embodiment, controlling permeation of the sub-layer through theveneer layer may comprise abrasive machining the veneer layer prior toapplying pressure to the veneer layer and/or the substrate.

In one embodiment, controlling permeation of the sub-layer through theveneer layer may comprise brushing the veneer layer prior to applyingpressure to the veneer layer and/or the substrate.

By abrasive machining and/or brushing the veneer layer, holes, cavitiesand/or cracks are formed in the veneer layer. Abrasive machining and/orbrushing the veneer layer may enlarge existing holes, cavities and/orcracks, and/or form new holes, cavities and/or cracks. By forming, orenlarging existing, holes, cavities, and cracks, the sub-layer permeatesmore easily through the veneer layer. Thereby, the permeation of thesub-layer through the veneer layer is increased, and the design of theveneer layer can be controlled and changed.

The veneer layer may be brushed prior to being applied on the sub-layer,or when being applied on the sub-layer. The same applies to abrasivemachining and/or processing of the veneer layer.

Abrasive machining of the veneer layer may be performed by an abrasivetool. The abrasive tool may be a brushing device. The abrasive tool maybe brush filaments, abrasive strips, sanding belts, sanding disks,grinding wheels, cutting tools such as water jet, etc.

The veneer layer may be processed by an abrasive tool such that veneermaterial with low density is removed while veneer material with higherdensity remains. The abrasive tool may be harder than at least portionsof the veneer layer.

Both surfaces, or only one of the surfaces, of the veneer layer, may bemachined abrasively. A lower surface of the veneer layer adapted to facethe sub-layer may be machined. An upper surface of the veneer layeradapted to facing upwards may be machined. By machining abrasively theupper surface of the veneer layer, flowing of the sub-layer in adirection parallel to the surface of the veneer layer is increased. Bymachining abrasively the lower surface of the veneer layer, thesub-layer may fill cavities formed in the lower surface of the veneerlayer.

Machining abrasively may be performed at different levels in the veneerlayer. Cavities, holes and/or cracks may be extending through the veneerlayer, or may extend partly through the veneer layer. The depth of thecavities, holes and/or cavities may substantially equal the thickness ofthe veneer layer, or may be less than the thickness of the veneer layer.

Machining the veneer layer prior to applying pressure may also becombined with machining performed after pressure has been applied toform the veneered element.

The abrasive machining and/or processing of the veneer layer may, forexample, include brushing, sanding, grinding, blasting, localcompressing, tearing, splitting, compressed air, etc.

Controlling permeation of the sub-layer through the veneer layer maycomprise processing the veneer layer prior to applying pressure to theveneer layer and/or the substrate. Such processing may include heating,for example, by thermal radiation, convective heating, and/or conductiveheating, steaming, and/or drying veneer prior to applying pressure tothe veneer layer and/or the substrate. Permeation may also be controlledby applying additives to the veneer layer adjusting the permeation ofthe sub-layer through the veneer layer. As an example, an additivereducing permeation of the sub-layer through the veneer layer, forexample, by blocking permeation, may be applied. Alternatively or incombination, an additive degrading the veneer layer, thus increasingpermeation may also be applied on the veneer layer.

Controlling permeation of the sub-layer through the veneer layer maycomprise compressing the veneer prior to applying the veneer on thesub-layer. By compressing the veneer, the density of at least portionsof the veneer is increased, thus reducing permeation of the sub-layerthrough at least portions of the veneer layer during pressing.Compressing may be performed by pressing plates and/or rollers withembossings. The compression, preferably combined with heating,preferably heating to a temperature exceeding 100° C., may result in aremaining increase in density.

Controlling permeation of the sub-layer through the veneer layer maycomprise controlling a fluid pressure of the sub-layer during pressing.A fluid pressure of the sub-layer is formed by applying pressure to theveneer layer and/or the substrate. In one embodiment, the sub-layer maybe in fluid form when applied on the substrate, or may be transformedinto fluid form by applying heat and pressure, such as the case for athermosetting binder applied in powder form. By increasing the fluidpressure, a larger amount of the sub-layer permeates through the veneerlayer, and/or longer way through the veneer layer, and/or permeates intothe veneer layer in a direction parallel to a plane of the veneer layer,such that larger spots of the sub-layer are visible from the surface ofthe veneer layer. Furthermore, when the sub-layer includes athermosetting binder, the cross-linking reaction results in forming ofcondensation water, transforming into steam under the applied heat andpressure, thereby increasing the fluid pressure. The cross-linking alsoresults in solidification of a part of the sub-layer, thus furtherpressing remaining uncured binder of the sub-layer.

Controlling the fluid pressure of the sub-layer may comprise adjusting aconcentration of a binder in the sub-layer. By increasing theconcentration of the binder in the sub-layer, the part of the sub-layerthat flows when heat and pressure are applied increases, and thereby alarger part of the sub-layer may permeate through the veneer layer. Whenthe binder flows, the binder brings any pigments to upper parts of theveneer.

Controlling the fluid pressure of the sub-lay may comprise adjusting thetype of binder used in the sub-layer. Different binders have differentproperties, such as how fast the binder cures and hardens. When using abinder that cures rapidly, less permeation of the sub-layer occurscompared to a binder that cures more slowly, thus being in liquid formover a longer time and allowing permeation through the veneer layer.

Controlling the fluid pressure of the sub-layer may comprise adjustingthe formulation of the binder of the sub-layer, such that properties ofthe sub-layer is controlled and adjusted.

The design of the veneered element may also be performed by controllinga ratio between pigment and binder of the sub-layer. By adjusting thebinder concentration, and the ratio pigment/binder, the amount ofpigment permeating through the veneer layer can be controlled. Thebinder brings the pigments when the binder flows during pressing. Theamount of pigment that permeates through the veneer layer may also becontrolled and adjust by choosing the size of the pigment particles.Smaller pigment particles permeate more easily through the veneer layerthan larger pigment particles.

Controlling the fluid pressure may comprise adjusting the moisturecontent of the sub-layer. By increasing the moisture content of thesub-layer, more steam is formed when heat and pressure is applied, whichforms an increased fluid pressure and thereby increased permeation ofthe sub-layer through the veneer layer. Contrary, if less permeation isdesired, the moisture content of the sub-layer may be decreased, forexample by drying before pressing.

Controlling the fluid pressure may comprise adjusting the pressureapplied to the veneer layer and/or the substrate. By increasing thepressure, the fluid pressure of the sub-layer is increased. Byincreasing the fluid pressure, a larger amount of the sub-layerpermeates through the veneer layer as described above.

Controlling the fluid pressure may comprise generating a gas pressure inthe sub-layer. The gas pressure increases the fluid pressure of thesub-layer, thus resulting in that the sub-layer permeates through thesub-layer in an increased extent.

Generating the gas pressure may comprise including chemical and/orphysical blowing agents in the sub-layer. When reacting, the chemicaland/or physical blowing agents form a gas pressure in the sub-layer.

Controlling permeation of the sub-layer through the veneer layer maycomprise including fillers in the sub-layer. By increasing the amount offillers in the sub-layer, the less the sub-layer permeates through theveneer layer. The fillers may reduce flowing of the sub-layer such thatthe sub-layer permeates more difficult through the veneer layer.Furthermore, some fillers, for example, wood particles, absorb thebinder to a certain degree, thereby reducing the amount of free binder,which may permeate through veneer layer, and thereby also reduce thefluid pressure. The fillers may comprise wood particles such aslignocellulosic and/or cellulosic particles. The wood particles may beat least partially bleached.

Controlling the permeation of the sub-layer through the veneer layer maycomprise adjusting the thickness of the sub-layer, for example byadjusting the amount of the sub-layer applied. If the sub-layer isapplied as a powder, controlling the permeation of the sub-layer throughveneer layer may be controlled by adjusting the amount of powder appliedfor forming the sub-layer. By applying a larger amount of powder forforming the sub-layer, the sub-layer permeates through the veneer layerto an increased extent.

Controlling permeation of the sub-layer through the veneer layer maycomprise forming holes and/or cracks in the veneer layer. The holesand/or cracks facilitate the sub-layer to permeate through the veneerlayer. Forming holes and cracks reduces resistance for the sub-layer forpermeating through the veneer layer. Forming holes, cavities and/orcracks may be performed by brushing prior to applying pressure to theveneer layer and/or the substrate. The holes, cracks and cavities may bepre-existing but enlarged, and/or may be newly formed holes, cracks andcavities.

Controlling permeation of the sub-layer through the veneer layer maycomprise controlling a thickness of the veneer layer. The thinner veneerlayer, the less distance for the sub-layer to travel until the sub-layeris visible on the top surface of the veneer layer.

Said at least a portion of the sub-layer may permeate through pores ofthe veneer layer. A veneer is a porous structure, including pores inwhich the sub-layer may permeate.

Said at least a portion of the sub-layer may permeate through cracks andholes of the veneer layer.

After pressing, the veneer layer may be mechanically/and or chemicallytreated such that a desired appearance of the veneered element isobtained. For examples, the veneer layer may be brushed and/or sandedafter pressing.

The veneer layer may comprise a wood veneer, a cork veneer, or stoneveneer. The veneer layer has a porous structure, and a portion ofsub-layer may permeate through the veneer layer. The wood veneer may becut veneer, sawn veneer, rotary cut veneer, and/or half-round cutveneer.

The sub-layer may comprise a binder.

The sub-layer may comprise a thermosetting binder. The thermosettingbinder may be an amino resin such as melamine formaldehyde, ureaformaldehyde, phenol formaldehyde, or a combination thereof. Thethermosetting binder simultaneously bonds the veneer layer to thesub-layer. When heat and pressure is applied to the sub-layer, thethermosetting binder becomes fluid before cross-linking takes place. Theapplied heat and pressure results in curing of the thermosetting binderof the sub-layer, simultaneously as bonding the veneer layer to thesub-layer.

The sub-layer may comprise a thermoplastic binder. The thermoplasticbinder may be polyvinyl chloride (PVC), polyethylene (PE), polypropylene(PP), polyurethane (PU), polyvinyl alcohol (PVOH), polyvinyl butyral(PVB), and/or polyvinyl acetate (PVAc), or a combination thereof. Thethermoplastic binder simultaneously bonds the veneer layer to thesub-layer.

The sub-layer may be substantially formaldehyde free.

The sub-layer may further comprise pigments. Thereby, the veneer layermay be coloured by the parts of the sub-layer penetrating through theveneer layer. The sub-layer may be pigmented to one or several differentcolours. By using a sub-layer containing different colours, differentparts of the veneer layer and/or different veneers may obtain differentcolours. The pigments may be brought by the flowable binder to an upperpart of the veneer layer. The pigments may provide a colour being darkeror lighter than the natural colour of the veneer. The pigment may bewhite, such as TiO2. White pigments, such as TiO2, may be combined withat least partially bleached wood particles, for example, to form a palestaining of the veneer.

The sub-layer may comprise wear resistant particles. Wear resistantparticles which are brought by the binder of the sub-layer to an upperpart of the veneer layer provide wear resistance to the veneer layer.

The substrate may be a wood-based board, for example, a wood-fibre basedboard such as MDF or HDF, or plywood. The substrate may be a WoodPlastic Composite (WPC). The substrate may be a mineral composite board.The substrate may be a fibre cement board. The substrate may bemagnesium oxide cement board. The substrate may be a ceramic board. Thesubstrate may be a plastic board such as a thermoplastic board.

The substrate may be a sheet such as paper sheet.

The fluid pressure may be uniformly distributed. Thereby, an essentiallyuniform permeation of the sub-layer through the veneer layer may beobtained, if the veneer layer has an essentially uniform structure. Anessentially uniform colouring of the veneer layer may also be obtained,if the veneer layer has an essentially uniform structure.

The fluid pressure may be non-uniformly distributed. By the fluidpressure being non-uniformly distributed, the degree of permeation ofthe sub-layer may vary of the surface of the veneer and non-uniformpattern may be obtained.

The method may further comprise digital printing a pattern in thesub-layer prior to applying the veneer layer on the sub-layer. Themethod may further comprise digital printing a pattern on the veneerlayer, prior or after pressing.

The veneer layer may be a continuous layer or a discontinuous layer ofveneers. The veneer layer may be formed of several veneers pieces. Theveneer layer may be formed of several pieces of veneer, forming apatchwork of veneers. The sub-layer may fill the gaps between the veneerpieces.

After pressure has been applied, the veneer layer may comprise embossedportions. A portion of the sub-layer may be more compressed under anembossed portion than under a non-embossed veneer layer portion.

The embossed portions may be naturally occurring after pressing. Forwood veneers having a porous structure, such as hard wood (e.g.,angiosperm), porous portions of the veneer form embossed portions afterpressing, since these portions do not spring back from their compressedstate when the pressure is released. These porous portions are filledwith the binder of the sub-layer during pressing. Then the binder curesand/or hardens, the binder locks the position of the porous portions inthe compressed state. The portions of veneer having high density, i.e.being non-porous, are compressed during pressing but spring back whenthe pressure is released, thus forming protrusions of the surface layer.The high-density portions do not absorb enough binder from the sub-layerto be locked by the hardened binder after pressing.

For wood veneer having a non-porous structure, such as soft wood (e.g.,gymnosperm), the summer wood annual rings (also called late wood annualrings), having high density, are not compressible during pressing.Instead, the summer wood annual rings are pressed into the sub-layersuch that the sub-layer is compressed. The summer wood annual rings formembossed portions of the surface layer. The spring wood annual rings(also called early wood annual rings) are compressible during pressing.During pressing, the spring wood annual rings are compressed. Then thepressure is released, the spring wood annual rings spring back, and formprotrusions.

The embossed portions of the surface layer may also be formed bypressing by an embossed pressing device, such as an embossed pressplate.

The method may further comprise applying a balancing layer on a surfaceof the substrate being opposite the veneer layer. The balancing layermay be a powder based balancing layer being applied as a powder. Thepowder based balancing layer may comprise wood particles such aslignocellulosic and/or cellulosic particles and a binder, preferably athermosetting binder such as an amino resin. The balancing layer may bea resin impregnated paper, preferably impregnated with a thermosettingbinder.

According to a second aspect of the invention, the present invention isrealised by a veneered element. The veneered element comprises asubstrate, a sub-layer arranged on the substrate, and a veneer layerarranged on the sub-layer, and wherein at least a portion of thesub-layer is permeated through the veneer layer.

At least a portion of the sub-layer may be visible at the surface of theveneer facing away from the substrate.

Preferably, a protective layer comprising thermoplastic material isarranged on the veneer layer.

An advantage of at least certain embodiments is that the protectivelayer comprising the thermoplastic material protects the veneer layer.By arranging a protective layer comprising thermoplastic material on theveneer layer, a substrate having a veneer surface layer being waterproofmay be obtained. The protective layer contributes with water resistantproperties to the veneer layer, such that a waterproof surface layer isobtained, wherein the decorative properties are formed by the veneerlayer.

Furthermore, the gloss level of the protective layer may be determinedby the press plate when pressing the protective layer to the veneerlayer.

The protective layer is preferably transparent, or at leastsubstantially transparent.

The protective layer may comprise at least one thermoplastic foil.

The thermoplastic material may comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The protective layer maycomprise more than one thermoplastic material.

The protective layer may comprise one or more layers, wherein the layermay comprise different thermoplastic materials, or thermoplasticmaterial of the same type.

The protective layer may further comprise wear resistant particles. Thewear resistant particles may be arranged between a first and a secondlayer of the protective layer. Alternatively, the wear resistantparticles may be arranged on the veneer layer below the protectivelayer. At least some of the wear resistant particles will protrude fromupper portions of the protective layer, or be arranged in the upperportions of the protective layer, after pressing. Thereby, the wearresistant particles provide wear resistance to the protective layer.

The protective layer may formed of the thermoplastic material in powderbe mixed with wear resistant particles.

The first and second thermoplastic material may be any of polyvinylchloride (PVC), polyester, polypropylene (PP), polyethylene (PE),polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET),polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.

In one embodiment, the first thermoplastic material is polyvinylchloride (PVC). The second thermoplastic material may be polyurethane(PU). Compared to a conventional protective layer substantiallyconsisting of polyvinyl chloride, a protective layer comprising an upperportion of polyurethane obtains improved chemical resistance. Its scuffresistance and micro scratch resistance are also improved. An upperlayer of PU also provides improved resistance against black heel mark.

The sub-layer may further comprise pigments.

The sub-layer may comprise fillers. The fillers may be particles orfibres, for example wood fibres or particles, or mineral particles orfibres. The wood particles may be lignocellulosic particles and/orcellulosic particles. The wood particles may be at least partiallybleached.

The sub-layer may comprise wear resistant particles.

The substrate may be a wood-based board, for example, a wood-fibre basedboard such as MDF or HDF, or plywood. The substrate may be a WoodPlastic Composite (WPC). The substrate may be a mineral composite board.The substrate may be a fibre cement board. The substrate may bemagnesium oxide cement board. The substrate may be a ceramic board. Thesubstrate may be a plastic board such as a thermoplastic board.

The at least a portion of the sub-layer may be permeated through poresof the veneer layer.

The veneer layer may comprise a wood veneer, a cork veneer, or a stoneveneer.

The veneer layer may comprise embossed portions. A portion of thesub-layer may be more compressed under an embossed portion than under anon-embossed veneer layer portion.

The embossed portions may be naturally occurring after pressing. Forwood veneers having a porous structure, such as hard wood (e.g.,angiosperm), porous portions of the veneer form embossed portions afterpressing, since these portions do not spring back from their compressedstate when the pressure is released. These porous portions are filledwith the binder of the sub-layer during pressing. Then the binder curesand/or hardens, the binder locks the position of the porous portions inthe compressed state. The portions of veneer having high density, i.e.being non-porous, are compressed during pressing but spring back whenthe pressure is released, thus forming protrusions of the surface layer.The high-density portions do not absorb enough binder from the sub-layerto be locked by the hardened binder after pressing.

For wood veneer having a non-porous structure, such as soft wood (e.g.,gymnosperm), the summer wood annual rings (also called late wood annualrings), having high density, are not compressible during pressing.Instead, the summer wood annual rings are pressed into the sub-layersuch that the sub-layer is compressed. The summer wood annual rings formembossed portions of the surface layer. The spring wood annual rings(also called early wood annual rings) are compressible during pressing.During pressing, the spring wood annual rings are compressed. Then thepressure is released, the spring wood annual rings spring back, and formprotrusions.

The embossed portions of the surface layer may also be formed bypressing by an embossed pressing device, such as an embossed pressplate.

The method may further comprise applying a balancing layer on a surfaceof the substrate being opposite the veneer layer. The balancing layermay be a powder based balancing layer being applied as a powder. Thepowder based balancing layer may comprise wood particles such aslignocellulosic and/or cellulosic particles and a binder, preferably athermosetting binder such as an amino resin. The balancing layer may bea resin impregnated paper, preferably impregnated with a thermosettingbinder.

The veneered element according to the second aspect of the presentinvention incorporates all the advantages of the method, whichpreviously has been discussed, whereby the previous discussion isapplicable also for the veneered element.

According to a third aspect of the invention, a method of producing anelement is provided. The method comprises

-   -   providing a substrate,    -   applying a sub-layer on a first surface of the substrate,    -   applying a surface layer having a porous structure on the        sub-layer, and    -   applying pressure to the surface layer and/or the substrate,        such that a least a portion of the sub-layer is permeating        through the porous structure of the surface layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will by way of example be described in more detailwith reference to the appended schematic drawings, which showembodiments of the present invention.

FIGS. 1a-c illustrates embodiments of a method of a producing a veneeredelement according to embodiments.

FIG. 2 illustrates an embodiment of a veneered element.

FIG. 3 illustrates a cross-section of a veneered element.

FIG. 4 illustrates an embodiment of a veneered element.

FIG. 5 illustrates an embodiment of a veneered element.

DETAILED DESCRIPTION

FIGS. 1a-c show embodiments of a method of producing a veneered element10. The veneered element 10 may be a furniture component, a buildingpanel such as a floor panel, a ceiling panel, a wall panel, a doorpanel, a worktop, skirting boards, mouldings, edging profiles, etc. Themethod comprises providing a substrate 1. The substrate is preferably apre-fabricated substrate, manufactured prior to the method of producingthe veneered element 10. The substrate 1 may be a board, for example, awood-based board as shown in the embodiment shown in FIGS. 1-4. Thewood-based board may be a wood fibre based board such as MDF, HDF,particleboard etc., or a plywood board. In other embodiments, thesubstrate may be a Wood Plastic Composite (WPC). The substrate may be amineral composite board. The substrate may be a fibre cement board. Thesubstrate may be magnesium oxide cement board. The substrate may be aceramic board. The substrate may be a plastic board such as athermoplastic board. In another embodiment, the substrate 1 may be acarrier such as sheet of paper or non-woven as shown in FIG. 5, or aconveyor.

A sub-layer 2 is applied on a first surface 4 of the substrate 1. In theembodiment shown in FIG. 1a , the sub-layer 2 is applied in powder form21. The powder 21 adapted to form the sub-layer 2 is applied byscattering, as shown in FIG. 1a . The sub-layer may also be applied asgranules. In other embodiments, the sub-layer 2 may be applied as aliquid, as a paste, a sheet, etc. The sub-layer 2 may be applied byroller coating, spraying, etc.

In one embodiment, the sub-layer 2 comprises a sheet impregnated with athermosetting binder. The sheet may be paper sheet. The sheet may becoloured, and/or the binder solution used to impregnate the sheet may becoloured, such that sheet becomes coloured during impregnation.

The sub-layer 2 comprises a binder. The binder may be a thermosettingbinder, a thermoplastic binder, or a combination thereof. The binder maybe wood mastic, wood filler or any other type of putty-like paste. Thethermosetting binder may be an amino resin such as melamine formaldehyderesin, phenol formaldehyde resin, urea formaldehyde resin, or acombination thereof. Urea formaldehyde resin may be used, alone or incombination with melamine formaldehyde resin, to reduce tension formedby the sub-layer 2 during curing, compared to when melamine formaldehyderesin is used only. The thermoplastic binder may be polyvinyl chloride(PVC), polyethylene (PE), polypropylene (PP), polyurethane (PU),polyvinyl alcohol (PVOH), polyvinyl butyral (PVB), polyvinyl acetate(PVAc), and/or thermoplastic elastomer (TPE), or a combination thereof.

The binder may be in powder form when applied.

The sub-layer 2 may be formed of a mix comprises a binder of the abovedescribed type and fillers. The mix may further comprise pigments. Themix may further comprise additives. The mix may further comprise wearand/or scratch resistant particles. As an alternative to a mix, thebinder, fillers, pigments, additives and any other component may beapplied separately on the substrate 1.

The fillers may be particles or fibres, for example wood fibres orparticles, or mineral particles or fibres. The wood particles may belignocellulosic particles and/or cellulosic particles. The woodparticles may be at least partially bleached. The fillers may be rice,straw, corn, jute, linen, flax, cotton, hemp, bamboo, bagasse or sisalparticles or fibres. The sub-layer may comprise starch such as maizestarch, potato starch, etc.

The fillers may be fillers having sound-absorbing properties such ascork particles and/or barium sulphate (BaSO4). Alternatively, asound-absorbing layer, for example a cork layer or cork veneer layer,may be arranged as an intermediate layer. The sub-layer is applied onthe sound-absorbing layer. The sound-absorbing layer may be arranged onthe substrate, or on a sub-layer arranged on the substrate.

The pigments may be darker than the natural colour of the veneer layer,and/or be paler that the natural colour of the veneer layer. Thepigments may include white pigments such as TiO2. A pigment such as TiO2can combined with at least partially bleached wood particles to obtain awhite staining of the veneer by the permeation of the sub-layer throughthe veneer. In one embodiment, a pre-mix is formed by white pigmentssuch as TiO2 and wood particles, preferably at least partially bleachedwood particles. The pre-mix is then mixed with remaining wood particles,binder, additives etc.

The additives may be wetting agents, anti-static agents such as carbonblack, and heat-conducting additives such as aluminium. Other possibleadditives are magnetic substances.

The sub-layer 2 may also comprise a foil or a sheet.

Additives such as blowing agents may be included in the sub-layer. Theblowing agents may be physical foaming agents such as EXPANCEL® and/orchemical blowing agents such as AIBN (azoisobutyronitrile) or ADC(azodicarbonamide).

The wear and/or scratch resistant particles may be aluminium oxideparticles and/or silica particles.

In one embodiment, the sub-layer 2 consists essentially of the binderand optionally additives, meaning that at least 90% of the sub-layer 2is the binder and optional additive(s). In one embodiment, the sub-layer2 is free from any fibres and/or fillers.

The sub-layer 2 may be applied in an amount of 200-600 g/m2, preferably300-500 g/m2 such as about 400 g/m2. The amount of binder applied forthe sub-layer 2 may be 100-300 g/m2, preferably 150-250 g/m2 such asabout 200 g/m2. The sub-layer 2 may comprise the binder in an amount of30-80 wt %, preferably in an amount of 40-60 wt % such as about 50 wt %.

The sub-layer 2 may be pre-pressed prior to applying the veneer layer 3.

A veneer layer 3 is applied on the sub-layer 2. The veneer layer 3 maybe a wood veneer, a cork veneer, or a stone veneer. The veneer has aporous structure, thus being permeable. The veneer layer 3 may have athickness of about 0.2 to 1 mm. The veneer layer 3 may be continuous ornon-continuous. The veneer layer 3 may be formed of several veneerpieces. The veneer pieces may be over-lapping or non-overlapping. A gapmay be formed between the veneer pieces. The gap may be filled by thesub-layer 2 after pressing. The veneer pieces may be applied randomly orforming a pattern. A patchwork of veneer pieces may be formed. Theveneer pieces may be arranged in a pattern such as a herringbonepattern, Dutch pattern etc., with several veneer pieces arranged on onesubstrate 1. The veneer pieces may also be arranged such that the veneerpieces, or the gap between the veneer pieces, forma template.

The sub-layer 2 may have a uniform colour, different shades, ordifferent portions of the sub-layer may have different colours. Amulti-coloured veneer layer 3 may be formed by colouring differentportions of the sub-layer 2 in different colours. If the veneer layer 3is formed by several veneer pieces, a first set of veneer pieces may bedifferently coloured than a second set of veneer pieces. Alternatively,each veneer piece may be differently coloured by the sub-layer beingdifferently coloured under each veneer piece.

In one embodiment, a digital print may be printed in the sub-layer 2,preferably by an ink jet printer. The different colours of the printpermeate through the veneer layer 3 such that the colouring of thesub-layer 2 is transferred into the surface of the veneer layer 3. Thecolouring and/or pattern of the sub-layer 2 may also be obtained by abinder and print technique (BAP), for example as described inWO2014/017972. In one embodiment, a digital print is printed on theveneer layer 3.

More than one veneer layer 3 may be arranged on a core. In oneembodiment, a first veneer layer may be arranged on the substrate 1, asub-layer 2 of the above described type is arranged on the first veneerlayer, and a second veneer layer is arranged on the sub-layer 2. Agroove may be formed, for example after pressing, in the second veneerlayer and in the sub-layer 2 such as the first veneer layer is visible.A gap may also be arranged between different portions of the secondveneer layer such that the sub-layer and/or the first veneer layer isvisible. The veneer layer may also comprise veneer pieces arrangedcrosswise.

In the embodiment shown in FIG. 1b , a protective layer 11 is arrangedon the veneer layer 3. The protective layer 11 comprises a thermoplasticmaterial. After the protective layer 11 has been arranged on the veneerlayer 3, pressure is applied to the veneer layer 3, via the protectivelayer 11, and/or the substrate 1 such that a fluid pressure is formed inthe sub-layer 2. The pressure may be applied by continuous press 30 orin a discontinuous press (not shown). Preferably, heat is also applied.The gloss level of the protective layer may be determined and changed bythe press plate or press belt when pressing the protective layer to theveneer layer. Different gloss levels may be obtained by a pressingdevice having different gloss. The pressing device may also compriseembossed portion such that a structured protective layer 11 is obtained.

In the embodiment shown in FIG. 1c , pressure is applied to the veneerlayer 3 and/or the substrate 1 such that a fluid pressure is formed inthe sub-layer 2. The pressure may be applied by continuous press 30 orin a discontinuous press (not shown). Preferably, heat is also applied.In a subsequent step, a protective layer 11 is applied to the veneerlayer 3. The protective layer 11 comprises a thermoplastic material. Theprotective layer 11 may be attached to the veneer layer 3 by anyconventional means, such as pressing, gluing etc. In the embodimentshown in FIG. 1c , pressure is applied to the protective layer 11 and/orthe substrate 1 in a continuous press 31 for attaching the protectivelayer 11 to the veneer layer 3. The pressure may also be applied in astatic press (not shown). The gloss level of the protective layer may bedetermined and changed by the press plate or press belt when pressingthe protective layer to the veneer layer. Different gloss levels may beobtained by a pressing device having different gloss. The pressingdevice may also comprise embossed portion such that a structuredprotective layer 11 is obtained.

The protective layer may also be attached to at least a portion of anedge surface of the substrate, for example, a bevel formed along an edgeof the substrate. Thereby, also an edge portion of the substrate isprotected by the protective layer such that the water resistance of theveneered element is further improved. For example, the width of theprotective layer applied may exceed the width of the substrate, suchthat the protective layer can be bent over the edge of the substrate andattached to an edge portion of the substrate.

Prior to applying the protective layer 11, the veneer layer may betreated in different ways. For example, the veneer layer 3 may bebrushed after pressing. The veneer layer 3 may be mechanically and/orchemically treated after pressing.

In both the embodiment shown in FIGS. 1b and in FIG. 1c , the protectivelayer 11 is in form of a thermoplastic foil. The thermoplastic foilcomprises a thermoplastic material. The thermoplastic material maycomprise polyvinyl chloride (PVC), polyester, polypropylene (PP),polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethyleneterephthalate (PET), polyacrylate, methacrylate, polycarbonate,polyvinyl butyral, polybutylene terephthalate, or a combination thereof.The thermoplastic foil may comprise one or several layers. The layersmay comprise the same thermoplastic material, or different thermoplasticmaterials. In one embodiment, the protective layer 11 comprises applyinga first foil comprising a first thermoplastic material, preferablypolyvinylchloride (PVC), on the veneer layer (3), and applying a secondfoil comprising a second thermoplastic material, preferably polyurethane(PU), on the first foil.

The thermoplastic foil may be provided as a continuous web, as shown inFIGS. 1b and 1c . The thermoplastic foil may be provided as sheets.

The protective layer 11 may comprise wear resistant particles. The wearresistant particles may be applied on the veneer layer 3 prior to applythe thermoplastic foil. The wear resistant particles may be appliedbetween two different layers of the protective layer 11. The wearresistant particles may be applied on the protective layer 11. The wearresistant particles may be aluminium oxide particles such as aluminium.Alternatively, or as a complement, the wear resistant particles may becarborundum, quartz, silica, glass, glass beads, glass spheres, siliconcarbide, diamond particles, hard plastics, reinforced polymers andorganics. The wear resistant particles preferably have a size of 10-200μm, preferably 50-100 μm. The wear resistant particles may have anirregular shape. The refractive index of the wear resistant particles 4may be 1.4-1.7.

Also scratch resistant particles may be applied in a similar manner.

In an embodiment (not shown), the protective layer 11 is applied byapplying a thermoplastic material in powder form on the veneer layer 3.The thermoplastic material may comprise polyvinyl chloride (PVC),polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS),polyurethane (PU), polyethylene terephthalate (PET), polyacrylate,methacrylate, polycarbonate, polyvinyl butyral, polybutyleneterephthalate, or a combination thereof. The protective layer may beapplied as one or several layers, comprising the same thermoplasticmaterial, or different thermoplastic materials. As described above, theprotective layer 11 formed by a thermoplastic material in powder formmay be applied, both prior to, and after, pressure has been applied tothe veneer layer 3 and/or the substrate 1.

Wear resistant particles of the above described type may be appliedtogether with the thermoplastic powder, preferably as mix comprising thethermoplastic material and the wear resistant particles. The mix mayfurther comprise scratch resistant particles. Alternatively, or as acomplement, wear resistant particles may be applied on the veneer layer3, prior to applying the thermoplastic material in powder form, or afterthe thermoplastic material in powder form has been applied.

In other embodiments, the protective layer 11 comprising a thermoplasticmaterial of the above described type may be applied in form of a slurryand/or paste on the veneer layer 3.

When sufficient pressure is applied as in the embodiment shown in FIG.1b or in the embodiment shown in FIG. 1c , the sub-layer 2 permeatesthrough pores, cracks and holes in the veneer layer 3. At least aportion of the sub-layer 2 permeates fully through the veneer layer 3such that said at least a portion of the sub-layer 2 becomes visible onthe veneer layer 3. Said at least a portion of the sub-layer, whichpermeates or transfers through the veneer layer 3, comprises at leastone component of the sub-layer 2. The matter of the sub-layer 2permeating through the veneer layer 3 may be one or several of thecomponents of the sub-layer 2. For example, the binder of the sub-layer2 may permeate through the veneer layer. The binder may bring anypigments of the sub-layer 2 to the upper surface of the veneer layer 3when melted during pressing.

The sub-layer 2 may be in fluid form or powder form when applied. Thebinder of the sub-layer 2, for example a thermosetting or thermoplasticbinder, may be applied as a powder or in fluid form as a dispersion,solution or suspension. If the binder is applied in powder form whenapplied, the binder melts when applying heat exceeding the melting pointof the binder at the pressure applied. Thereby, the binder is in liquidform. By applying a pressure, a fluid pressure of the sub-layer 2 isformed. Thereby, the binder in liquid form may permeate the veneer layer3. If a thermosetting binder is used, the thermosetting binder isfirstly dominated by a melting process up to a first temperature,thereafter the thermosetting binder is dominating by a crosslinkingprocess.

By controlling the degree of permeation of the sub-layer 2 through theveneer layer 3, the design of the veneered element 10 can be controlled.The design of the veneer can be changed by the sub-layer 2 at leastpartly permeating the veneer layer 3 and thus being visible at thesurface of the veneer layer 3. If the veneer layer 3 comprises cracks,cavities and other irregularities, the fluid pressure required topermeate completely through the veneer layer 3 is decreased, such thatportions of the sub-layer 2 easily permeates through the veneer layer 3and fills the crack or holes. Thereby, putty can be avoided or at leastreduced. By including pigments in the sub-layer 2, the design of theveneer can be changed further.

For some designs, a large degree of permeation may be desired, and forother designs, less, or varying, permeation may be desired. For example,if a uniform colouring of the veneer such as glazing, lazuring orstaining is desired, a uniform fluid pressure is preferred. Preferably,the veneer layer 3 has a uniform thickness and structure. If a varyingpermeation is desired, resulting in varying pattern of the veneer, avarying fluid pressure is preferred. The veneer layer 3 may have avarying structure including cracks and cavities. The thickness of theveneer layer 3 can also be controlled in order to control the permeationof the sub-layer 2 and thereby the design of the veneer layer 3. Thethinner the veneer layer 3 is, the larger amount of the sub-layer 2permeates through the veneer layer 3.

Controlling the design of the veneered element 10 by controlling thepermeation of the sub-layer 2 can be made in several ways. The fluidpressure may be controlled and adjusted. The fluid pressure may bevarying over the surface of the veneer layer 3. The fluid pressure canbe increased if a large degree of permeation of the sub-layer 2 isdesired. The fluid pressure can be decreased if less permeation of thesub-layer 2 is desired.

The fluid pressure can be controlled in several ways. The fluid pressurecan be controlled by controlling the pressure applied to the substrate 2and/or veneer layer 3. The temperature applied may have influence on thepermeation, for example by changing the viscosity of the sub-layer 2.

The fluid pressure may also be controlled by generating a gas pressurein the sub-layer 2. By generating a gas pressure inside the sub-layer 2,the fluid pressure increases. The gas pressure may be generated byincluding chemical and/or physical blowing agents in the sub-layer. Thechemical and/or physical blowing agents increase the fluid pressure whenactivated.

The fluid pressure of the sub-layer 2 may also be controlled byadjusting the concentration of binder in the sub-layer 2. By increasingthe concentration of the binder of the sub-layer 2, the more material ofthe sub-layer 2 may permeate through the veneer layer 3. The part of thesub-layer 2 that flows when heat and pressure is applied increases, andthereby a larger part of the sub-layer 2 may permeate through the veneerlayer 3. Furthermore, the type of binder may be adjusted. By increasingthe amount of a thermosetting binder in the sub-layer 2, the part of thesub-layer 2 being flowable when heat and pressure is applied increases,and thereby the fluid pressure.

The fluid pressure of the sub-layer 2 may also be controlled byadjusting the type of binder in the sub-layer 2. By using different typeof binders, the fluid pressure of the sub-layer 2 and thereby thepermeation can be altered. A rapidly curing binder forms less permeationof the sub-layer 2 through the veneer layer. The fluid pressure may alsobe controlled by adjusting the formulation of the binder of thesub-layer. Thereby, properties of the sub-layer can be controlled.

The fluid pressure may also be controlled by adjusting the moisturecontent of the sub-layer. The higher moisture content of the sub-layer,the more steam is formed when applying heat and pressure, therebyincreasing the fluid pressure, and consequently, permeation of thesub-layer 2 through the veneer layer 3. Contrary, by decreasing themoisture content of the sub-layer 2 before pressing, for example, bydrying the sub-layer 2, the less steam is formed during pressing.

Permeation of the sub-layer 2 through the veneer layer 3 may also becontrolled by including fillers in the sub-layer. The fillers reducepermeation of the sub-layer by reducing the flowing of the binder. Somefillers, such as wood particles and other organic fillers, absorb thebinder to some extent such that the remaining binder that is free topermeate through the veneer layer 3 is reduced. The fluid pressure isthereby also reduced.

Permeation of the sub-layer 2 through the veneer layer 3 may also becontrolled by adjusting the thickness of the sub-layer 2, for example byadjusting the amount of sub-layer applied. If the sub-layer 2 is appliedas a powder, the amount of powder applied can be adjusted in order toachieve the desired permeation of the sub-layer 2 through the veneerlayer 3. The thicker sub-layer, i.e. the larger amount of sub-layerapplied, the more the sub-layer 2 permeates through the veneer layer 3.

Permeation of the sub-layer 2 through the veneer layer 3 may also becontrolled by forming holes or cracks through the veneer layer 3. Byforming, or enlarging existing, holes and cracks, the sub-layer 2permeates easily through the veneer layer 3. Controlling permeation ofthe sub-layer 2 through the veneer layer 3 may be performed by forming,or enlarging existing cavities, holes and/or cracks, preferably bybrushing.

By adjusting and controlling these parameters, permeation of thesub-layer 2 through the veneer layer 3 can be controlled such that adesired look of the veneer surface is obtained, for example as shown inFIGS. 2-5.

In an embodiment, a produced building panel may be 6-25 mm thick,preferably 8-15 mm thick after pressing, while the core may be 5-22 mmthick, preferably 7-14 mm thick. The sub-layer may be 0.1-2 mm thickafter pressing.

Furthermore, a protective layer may be applied to the veneer layer 3.The protective layer may be a coating such as one or several lacquerlayers. The coating may be an acrylate or methacrylate coating such aspolyurethane coating. The coating may comprise wear and/or scratchresistant particles. The protective layer may be an overlay papercomprising wear resistant particles. The protective layer may be apowder overlay, as described in WO2011/129755, comprising processed woodfibres, a binder and wear resistant particles applied as mix on theveneer surface. If the protective layer comprises or is an overlay paperor a powder overlay, the protective layer is preferably applied beforethe step of applying heat and pressure. Thereby, the protective layer iscured and attached to the veneer layer in the same step as attaching theveneer layer to the sub-layer and to the substrate.

The veneered element 10 may further be treated in different ways, forexample brushed, oiled, lacquered, waxed, etc. After pressure has beenapplied, the veneer layer 3 may be mechanically/and or chemicallytreated such that a desired appearance of the veneered element 10 isobtained. For examples, the veneer layer 3 may be brushed and/or sandedafter pressing.

A protective coating may also be applied to the veneer layer 3 prior topressing. In one embodiment, a wax powder is applied, for example,scattered, on the upper surface of the veneer layer, facing away fromthe substrate 1, prior to pressing. During pressing, the wax powderforms a protective coating of the veneered element 10.

In one embodiment, a primer is applied on the upper surface of theveneer layer, facing away from the substrate 1, prior to pressing. Theprimer may be a print primer, a primer for preparing the veneer layer 3for lacquering, etc.

A protective foil may also be applied on the veneer layer 3 prior orafter pressing. The protective foil may be thermoplastic foil such as PUor PVC foil, as described above with reference to FIGS. 1b and 1 c.

In the embodiment in FIGS. 1-4, the substrate 1 comprises a wood-basedboard such as plywood, HDF, MDF, particleboard etc. In this embodimentthe veneered element 10 may be a building panel or a furniturecomponent. If the veneered element 10 is a floor or wall panel, thefloor or wall panel may be provided with a mechanical locking system forjoining with an adjacent floor or wall panel. The mechanical lockingsystem may be any of the types disclosed in WO 2007/015669, WO2008/004960, WO 2009/116926, or WO 2010/087752. If the veneered element10 is a furniture component for a drawer, shelf or other furniture, thefurniture may be provided with a mechanical locking system for joiningwith another part of the drawer, shelf or furniture component. Themechanical locking system may be of the type described in WO2012/154113.

The veneered element 10 may be provided with decorative grooves orbevels. The decorative grooves or bevels may be extending into thesub-layer 2 such that the sub-layer 2 is visible form the top surface ofthe veneered element. The decorative groove or bevel may be arrangedadjacent an edge of the veneered element provided with the mechanicallocking system. By providing a decorative groove extending into thesub-layer 2, a ship-decking appearance may be obtained.

In the embodiment in FIG. 2, the sub-layer 2 has permeated through theveneer layer 3 in some portions of the veneer layer 3 where theresistance of the veneer has been lower, for example as in cracks, holesand cavities of the veneer layer, but to a lower degree through otherparts of the veneer layer 3. Portions 2 a of the sub-layer 2 are visibleon the surface of the veneer layer 3 as shown in FIG. 2. The permeationof the sub-layer 2 forms an irregular design of the veneer.

FIG. 3 shows a cross-section of the veneered element 10 in more detail.FIG. 3 illustrates in more detail how portions 2 a of the sub-layer 2have permeated through the veneer layer 3 such that the portions 2 a ofthe sub-layer 2 are visible from an exposed surface of the veneer layer3. FIG. 3 illustrates that the sub-layer 2 has permeated through theveneer layer 3 and filled holes 6 of veneer such that portions 2 a ofthe sub-layer 2 are visible through the veneer layer 3. The hole 6 may,as in FIG. 3, be a knot. FIG. 3 also illustrates that the sub-layer 2has permeated through the veneer layer 3 and filled cracks 7 in theveneer such that portions 2 a of the veneer layer 3 are visible from theupper surface of the veneer layer 3. Furthermore, FIG. 3 shows thatportions 2 a of the sub-layer 2 have permeated through pores 8 of theveneer layer 3 such that portions 2 a of the sub-layer 2 are visible onthe upper surface of the veneer layer 3. In the embodiment shown in FIG.3, the substrate 1 comprises a wood based board such as plywood, HDF,MDF, particleboard etc. The veneered element 10 is also provided with abalancing layer 5 arranged on a second surface 9 of the substrate 1,opposite the sub-layer 2. The balancing layer 5 may be a powder basedbalancing layer being applied as a powder. The powder based balancinglayer may comprise wood particles such as lignocellulosic and/orcellulosic particles and a binder, preferably a thermosetting bindersuch as an amino resin. The balancing layer may be a resin impregnatedpaper, preferably impregnated with a thermosetting binder. The substrate1 is also provided with a protective layer 11. The protective layer 11may, for example, be a coating as described above or a protective layercomprising a thermoplastic material as described above with reference toFIGS. 1b and 1 c.

In FIG. 4, also showing a veneered element 10 of the above describedtype wherein the substrate 1 comprising a wood based board such asplywood, HDF, MDF, particleboard etc. Also in this embodiment theveneered element 10 may be a building panel or a furniture component,and may be provided with a mechanical locking system. However, in thisembodiment, compared to the embodiment shown in FIG. 2, permeation ofthe sub-layer 2 is more uniform through the veneer layer 3 such that amore regular design of the veneer layer 3 is obtained. This may beachieved by applying a uniform pressure, and by providing a veneer layer3 having a uniform porous structure and/or uniform thickness.

FIG. 5 shows an embodiment of the veneered element 10 of the abovedescribed type wherein the substrate 1 comprises a paper or a sheet. Thesubstrate 1 forms a carrier for the veneer layer 3 and the sub-layer 2.The veneered element 10 according to this embodiment may be bendableand/or flexible. Thereby, post-forming of the veneered element 10 ispossible. The veneered element 10 may be adhered to another element in alater operation. The veneered element 10 may form a surface of, forexample, a furniture component. In one embodiment, the substrate is aconveyor, and the veneered element 10 is removed from the conveyor afterheat and pressure have been applied.

It is contemplated that there are numerous modifications of theembodiments described herein, which are still within the scope of theinvention as defined by the appended claims.

It is contemplated that the sub-layer may not directly contact thesubstrate, but an intermediate layer arranged between the substrate andthe sub-layer may be provided.

It is also contemplated that the building panel may be provided with asecond veneer layer (not shown) of the above described type applied inthe same manner as described above. A sub-layer of the above describedtype is applied on a second surface of the substrate of the abovedescribed type. The second surface of the core faces away from theveneer layer described above with reference to FIGS. 1-4. In thisembodiment, the veneer layer described above with reference to FIGS. 1-4is considered as a first veneer layer, and the second veneer layer isarranged oppositely the first veneer layer. A design of the secondveneer layer is controlled by determining level of permeation of thesub-layer through the second veneer layer as described above withreference to FIGS. 1-5.

EXAMPLES Example 1

400 g/m2 of a powder mixture, comprising 40 wt-% wood fibres, 10 wt-%aluminium oxide (Alodur ZWSK 180-ST), 49.5 wt-% melamine formaldehyderesin (Kauramin 773) and 0.5 wt-% of carbon black (Printex 60), wasscattered on a 10.0 mm HDF board for forming a sub-layer. The powderlayer forming the sub-layer was sprayed with 20 g/m2 of an aqueoussolution of a release agent (PAT-660). A 0.6 mm oak veneer layer waspositioned on the sub-layer prior to pressing the assembly in a shortcycle press for 30 seconds at 40 bar with a press plate temperature of160° C. The resulting product was a veneered HDF having pores and cracksin the veneer layer filled with the cured powder mixture of thesub-layer.

Example 2

800 g/m2 of a powder mixture, comprising of 40 wt-% wood fibres, 10 wt-%aluminium oxide (Alodur ZWSK 180-ST), 49.5 wt-% melamine formaldehyderesin (Kauramin 773) and 0.5 wt-% of carbon black (Printex 60), wasscattered on a 10.0 mm HDF board for forming a sub-layer. The powderlayer forming the sub-layer was sprayed with 20 g/m2 of an aqueoussolution of a release agent (PAT-660). A 0.6 mm oak veneer waspositioned on the sub-layer prior to pressing the assembly in a shortcycle press for 30 seconds at 40 bar with a press plate temperature of160° C. The resulting product was a veneered HDF having cracks and anincreased amount of pores in the veneer layer filled with the curedpowder mixture of the sub-layer in comparison with the product ofexample 1.

Example 3

400 g/m2 of a powder mixture, comprising 17.5 wt-% wood fibres, 17.5wt-% mineral fibres 10 wt-% aluminium oxide (Alodur ZWSK 180-ST), 52.5wt-% melamine formaldehyde resin (Kauramin 773) and 0.5 wt-% of carbonblack (Printex 60), was scattered on a 10.0 mm HDF board for forming asub-layer. The powder layer forming the sub-layer was sprayed with 20g/m2 of an aqueous solution of a release agent (PAT-660). A 0.6 mm oakveneer was positioned on the sub-layer prior to pressing the assembly ina short cycle press for 30 seconds at 40 bar with a press platetemperature of 160° C. The resulting product was a veneered HDF havingcracks and a decreased amount of pores in the veneer layer filled withthe cured powder mixture of the sub-layer in comparison with the productof example 1.

Example 4

400 g/m2 of a powder mixture, comprising 10 wt-% aluminium oxide (AlodurZWSK 180-ST), 89.5 wt-% melamine formaldehyde resin (Kauramin 773) and0.5 wt-% of carbon black (Printex 60), was scattered on a 10.0 mm HDFboard for forming a sub-layer. The powder layer forming the sub-layerwas sprayed with 20 g/m2 of an aqueous solution of a release agent(PAT-660). A 0.6 mm oak veneer was positioned on the sub-layer prior topressing the assembly in a short cycle press for 30 seconds at 40 barwith a press plate temperature of 160° C. The resulting product was aveneered HDF having cracks and an increased amount of pores in theveneer filled with the cured powder mixture of the sub-layer incomparison with the product of the example 1.

Example 5

400 g/m2 of a powder mixture, comprising 40 wt-% wood fibres, 10 wt-%aluminium oxide (Alodur ZWSK 180-ST), 49.5 wt-% thermoplastic binder(Vinnapas 5010 N) and 0.5 wt-% of carbon black (Printex 60), wasscattered on a 10.0 mm HDF board for forming a sub-layer. The powderlayer forming the sub-layer was sprayed with 20 g/m2 of an aqueoussolution of a release agent (PAT-660). A 0.6 mm oak veneer waspositioned on the sub-layer prior to pressing the assembly in a shortcycle press for 30 seconds at 40 bar with a press plate temperature of160° C. The resulting product was a veneered HDF having a decreasedamount of pores and cracks in the veneer layer filled with the curedpowder mixture compared to the product of example 1.

Example 6

400 g/m2 of a liquid mixture, comprising 45 wt-% water, 10 wt-%aluminium oxide (Alodur ZWSK 180-ST), 44.5 wt-% melamine formaldehyderesin (Kauramin 773) and 0.5 wt-% of carbon black (Printex 60), wasapplied on a 10.0 mm HDF board for forming a sub-layer. A 0.6 mm oakveneer was positioned on the liquid layer forming the sub-layer prior topressing the assembly in a short cycle press for 30 seconds at 40 barwith a press plate temperature of 160° C. The resulting product was aveneered HDF having pores and cracks in the veneer layer filled with thecured mixture.

Example 7

200 g/m2 of a polyurethane powder (Desmomelt VP KA 8702) was applied ona 10.0 mm HDF board for forming a sub-layer. A 0.6 mm oak veneer waspositioned on the sub-layer prior to pressing. Wear resistant particlesin form of 40 g/m2 of aluminium oxide (Alodur ZWSK 180-ST) were appliedon the oak veneer prior to pressing. Further, a 0.05 mm polyurethanefilm (LPT 4802) was applied on the oak veneer with the wear resistantparticles prior to pressing. The assembly was pressed in a short cyclepress for 40 seconds at 20 bar with a temperature of 140° C. andthereafter cooled to 50° C. The resulting product was a veneered HDFhaving pores and cracks in the veneer layer filled with the sub-layer.The veneer layer was protected by the polyurethane film.

Example 8

210 g/m2 of a powder mix comprising 44 wt % wood fibre, 46 wt %phenol-formaldehyde resin (Prefere 4976), 5 wt % titanium dioxide and 5wt % aluminium oxide (Alodur ZWSK 180 ST-180) was applied on a 10.0 mmHDF board for forming a sub-layer. A 0.6 mm oak veneer was applied onthe sub-layer prior to pressing. A 0.05 mm polyurethane film (LPT4802)was applied on the oak veneer prior to pressing. The assembly waspressed in a short cycle press for 40 seconds at 20 bar with atemperature of 140° C. and thereafter cooled to 50° C. The resultingproduct was a veneered HDF having pores and cracks in the veneer layerfilled with the cured sub-layer. The veneer layer was protected by thepolyurethane film.

Example 9

300 g/m2 of a powder mix comprising 30.41 wt % wood fibre, 52.5 wt %melamine-formaldehyde resin (Kauramin 773), 3.4 wt % titanium dioxide,8.8 wt % aluminium oxide (Alodur ZWSK 180-ST), 4.7 wt % pigmentLichtgrau G10512, 0.15 wt % pigment Gelb 265 and 0.04 wt % pigmentcarbon black (Black 920) was applied on a 10.0 mm HDF board for forminga sub-layer. A 0.06 mm oak veneer was applied on the sub-layer prior topressing. A 0.05 mm polyurethane film (LPT 4802) was applied on theveneer prior to pressing. The assembly was pressed in a short cyclepress for 120 seconds at 20 bar and a temperature of 160° C. Theresulting product was a veneered HDF having pores and cracks in theveneer layer filled with the cured sub-layer. The veneer layer wasprotected by the polyurethane film.

Example 10

40 g/m2 of a polyurethane powder (Desmomelt VP KA 8702) was applied on a10.0 mm HDF board for forming a sub-layer. A 0.9 mm cork veneer wasapplied on the sub-layer prior to pressing. Wear resistant particles inform of 40 g/m2 aluminium oxide (Alodur ZWSK 180-ST) were applied on thecork veneer prior to pressing. A 0.05 mm polyurethane film (LPT 4802)was applied on the cork veneer and the wear resistant particles prior topressing. The assembly was pressed in a short cycle press for 40 secondsat 20 bar with a temperature of 140° C. and thereafter cooled to 50° C.The resulting product was a veneered HDF having pores and cracks in theveneer layer filled with the sub-layer. The veneer layer was protectedby the polyurethane film.

Example 11

40 g/m2 of a polyurethane powder (Desmomelt VP KA 8702) was applied on a10.0 mm HDF board for forming a sub-layer. A 0.9 mm cork veneer wasapplied on the sub-layer prior to pressing. A first 0.05 mm polyurethanefilm (LPT 4802) was applied on the cork veneer. Wear resistant particlesin form of 40 g/m2 aluminium oxide (Alodur ZWSK 180-ST) were applied onthe cork veneer prior to pressing. A second 0.05 mm polyurethane film(LPT 4802) was applied on the first polyurethane film and the wearresistant particles prior to pressing. The assembly was pressed in ashort cycle press for 40 seconds at 20 bar with a temperature of 140° C.and thereafter cooled to 50° C. The resulting product was a veneered HDFhaving pores and cracks in the veneer layer filled with the sub-layer.The veneer layer was protected by the polyurethane film.

The invention claimed is:
 1. A method of producing a veneered element,the method comprising providing a substrate, applying a sub-layer on asurface of the substrate, applying a veneer layer on the sub-layer,applying a protective layer comprising a thermoplastic material on theveneer layer, and applying pressure to the veneer layer and/or thesubstrate, such that at least a portion of the sub-layer permeatesthrough the veneer layer.
 2. The method according to claim 1, whereinthe thermoplastic material comprises polyvinyl chloride, polyester,polypropylene, polyethylene, polystyrene, polyurethane, polyethyleneterephthalate, polyacrylate, methacrylate, polycarbonate, polyvinylbutyral, polybutylene terephthalate, or a combination thereof.
 3. Themethod according to claim 1, wherein the protective layer comprises atleast one thermoplastic foil.
 4. The method according to claim 1,wherein applying the protective layer comprises applying a first foilcomprising a first thermoplastic material, on the veneer layer, andapplying a second foil comprising a second thermoplastic material, onthe first foil.
 5. The method according to claim 1, wherein applying theprotective layer comprises applying the thermoplastic material in powderform on the veneer layer.
 6. The method according to claim 1, whereinthe protective layer further comprises wear resistant particles.
 7. Themethod according to claim 1, wherein the sub-layer further comprisespigments.
 8. The method according to claim 1, wherein the substrate is awood-based board.
 9. The method according to claim 1, further comprisingcontrolling a design of the veneer layer by controlling permeation ofthe sub-layer through the veneer layer.
 10. The method according toclaim 9, wherein controlling permeation of the sub-layer through theveneer layer comprises controlling a fluid pressure of the sub-layer.11. The method according to claim 10, wherein controlling the fluidpressure of the sub-layer when applying pressure includes adjusting oneor more of the following parameters: concentration of a binder in thesub-layer; type of binder in the sub-layer; formulation of the binder inthe sub-layer; moisture content of the sub-layer; the pressure appliedto the veneer layer and/or the substrate; a gas pressure in thesub-layer; concentration of fillers in the sub-layer; and thickness ofthe veneer layer.
 12. The method according to claim 11, whereingenerating the gas pressure comprises including chemical and/or physicalblowing agents in the sub-layer.
 13. The method according to claim 9,wherein controlling permeation of the sub-layer through the veneer layercomprises abrasive machining of the veneer layer prior to applyingpressure to the veneer layer and/or the substrate.
 14. The methodaccording to claim 13, wherein the abrasive machining comprises brushingthe veneer layer prior to applying pressure to the veneer layer and/orthe substrate.
 15. The method according to claim 9, wherein controllingpermeation of the sub-layer through the veneer layer comprises formingholes, cavities and/or cracks in the veneer layer.
 16. The methodaccording to claim 1, wherein said at least a portion of the sub-layerpermeates through pores of the veneer layer.
 17. The method according toclaim 1, wherein said at least a portion of the sub-layer permeatesthrough cracks and/or holes of the veneer layer.
 18. The methodaccording to claim 1, wherein the veneer layer comprises a wood veneer,a cork veneer, or a stone veneer.
 19. The method according to claim 1,wherein the sub-layer comprises a binder.
 20. The method according toclaim 19, wherein the binder is a thermosetting binder or athermoplastic binder.
 21. The method according to claim 1, wherein thesub-layer comprises wear resistant particles.
 22. The method accordingto claim 1, wherein after pressure has been applied, the veneer layercomprises embossed portions, wherein a portion of the sub-layer is morecompressed under an embossed portion than under a non-embossed surfaceportion.
 23. A veneered element, comprising a substrate, a sub-layerarranged on the substrate, and a veneer layer arranged on the sub-layer,a protective layer comprising a thermoplastic material arranged on theveneer layer, and wherein at least a portion of the sub-layer ispermeated through the veneer layer such that at least a portion of thesub-layer is visible at the surface of the veneer layer facing away fromthe substrate.
 24. The veneered element according to claim 23, whereinthe protective layer further comprises wear resistant particles.
 25. Theveneered element according to claim 23, wherein the thermoplasticmaterial comprises polyvinyl chloride, polyester, polypropylene,polyethylene, polystyrene, polyurethane, polyethylene terephthalate,polyacrylate, methacrylate, polycarbonate, polyvinyl butyral,polybutylene terephthalate, or a combination thereof.
 26. The veneeredelement according to claim 23, wherein the protective layer comprises atleast one thermoplastic foil.
 27. The veneered element according toclaim 23, the protective layer comprises a first foil comprising a firstthermoplastic material, preferably polyvinylchloride (PVC), and a secondfoil comprising a second thermoplastic material, preferably polyurethane(PU).
 28. The veneered element according to claim 23, wherein thesub-layer comprises pigments.
 29. The veneered element according toclaim 23, wherein the sub-layer comprises wear resistant particles. 30.The veneered element according to claim 23, wherein the sub-layercomprises fillers.
 31. The veneered element according to claim 23,wherein said at least a portion of the sub-layer is permeated throughpores of the veneer layer.
 32. The veneered element according to claim23, wherein the veneer layer comprises embossed portions, wherein aportion of the sub-layer is more compressed under an embossed portionthan under a non-embossed surface portion.